Which principles of exercise science should trainers be familiar with?

B is the correct choice because trainers must be well-versed in fundamental principles of exercise science, which include anatomy, biomechanics, physiology, and the effects of exercise. These areas of knowledge form the foundation of effective training and program design, enabling trainers to create safe and effective workout plans tailored to individual client needs.

Understanding anatomy helps trainers know the muscles and systems involved in various movements, while biomechanics provides insight into the mechanical aspects of body movement, allowing for improved performance and injury prevention. Physiology is crucial for comprehending how the body responds to exercise, including adaptations that occur with regular training. Knowledge of the effects of exercise encompasses understanding both the short-term and long-term changes that exercise induces in the body, which is essential for designing programs that lead to specific outcomes.

In contrast, focusing only on nutrition and dieting, cardiovascular training techniques, or marketing and client retention does not provide the holistic knowledge necessary to effectively train clients and ensure their safety and success in an exercise program. Therefore, a comprehensive understanding of the principles of exercise science is vital for trainers aiming to support their clients in achieving fitness goals.